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Baroreflex sensitivity and its association with arrhythmic events in Chagas disease

Astrid Meireles Santos, Mauricio Ibrahim Scanavacca, Francisco Darrieux

    Arquivos Brasileiros De Cardiologia
    |July 9, 2014
    PubMed

    Insights

    Baroreflex sensitivity (BRS) impairment worsens with Chagas disease progression, correlating with complex ventricular arrhythmias, not ejection fraction. Lower BRS indicates higher arrhythmia risk.

    Area of Science:

    • Cardiology
    • Autonomic Nervous System Research
    • Chagas Disease Pathophysiology

    Background:

    • Sudden cardiac death is a primary cause of mortality in Chagas disease (CD), even with preserved ejection fraction (EF).
    • Autonomic modulation is implicated as a destabilizing factor for the arrhythmogenic substrate in CD.

    Purpose of the Study:

    • To assess baroreflex sensitivity (BRS) in different stages of Chagas disease.
    • To evaluate the association between BRS and the occurrence and complexity of ventricular arrhythmias.

    Main Methods:

    • ECG and continuous noninvasive blood pressure monitoring were performed on 42 CD patients.
    • Baroreflex sensitivity (BRS) was determined using the phenylephrine method.
    • Heart rate variability (HRV) and ejection fraction (EF) were also assessed.

    Main Results:

    • Baroreflex sensitivity (BRS) was significantly lower in patients with spontaneous sustained ventricular tachycardia (GIII) compared to those with undetermined CD (GI).
    • Lower BRS was associated with higher ventricular extrasystole (VE) density and complexity, independent of EF.
    • BRS was the sole predictor for the occurrence of sustained ventricular tachycardia (SVT).

    Conclusions:

    • Baroreflex sensitivity (BRS) is preserved in early-stage Chagas disease but declines as the disease progresses.
    • Impaired BRS is linked to more severe ventricular arrhythmias in Chagas disease patients.
    • Autonomic dysfunction, indicated by BRS, correlates with arrhythmia burden rather than ejection fraction.
    Abstract

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